Chapter 18 P-glycoproteins and xenobiotic efflux transport in fish

Abstract

Publisher Summary This chapter reviews the more recent data and focuses on P-glycoproteins (P-gp) in fish and general biochemistry of P-gp. Biological membranes are barriers for the uptake, distribution, and elimination of xenobiotics in organisms. According to a traditional view in toxicology, the bioaccumulation of organic chemicals occurs mainly passively, driven by the compound's hydrophobicity. Once bioaccumulated, the xenobiotic may undergo phase I and II biotransformation metabolisms, the products of which in general are less toxic than the mother compound. Hydrophobicity and biotransformation rate have traditionally been considered the main factors determining whether a compound is adequately detoxified. The chapter explains general aspects of P-glycoprotein and P-glycoproteins in aquatic animals. General aspect of P-glycoprotein is explained with the help of ATP binding cassette (ABC) transporters, functional and structural characteristics of P-glycoprotein, and physiological function of P-glycoprotein. The functional ABC transporter comprises multiple functional units organized in a characteristic fashion. The most astonishing characteristic of P-gp is that it transports structurally and functionally very diverse substrates.